Coolant likely cause of Volt fires, says AP source

GM is strengthening the Volt's battery pack to prevent coolant leaks in accidents.

Ironically, the liquid coolant that keeps the Volt's lithium-ion battery from overheating on the road is likely what caused it to catch fire three weeks after a crash test. But Volt drivers don't have to worry about coolant catching flame in the same way they might worry about gasoline spills. A source briefed on the Volt's investigation told the Associated Press that crystallized coolant resulted in an electrical short, causing the battery to catch fire.

The National Highway Transportation Safety Administration has been investigating the Chevrolet Volt in response to a fire that started in the vehicle's battery several weeks after it completed side-impact crash testing last June. NHTSA was not informed of, and did not follow, the Volt's post-crash safety protocol, which requires the battery to be drained of power.

GM and investigators have been examining all aspects of the 16kWh battery, including circuit boards, the chemical reaction that stores and discharges energy from the battery, and the coolant itself, to figure out what started the fires in dormant vehicles. Although the findings haven't been finalized, coolant is the likely culprit, sources say. GM believes that if they can prevent the coolant from leaking, they can prevent future battery fires, and they're close to a solution, according to a Reuters article.

Engineers are proposing to laminate the 400 pound battery's circuitry and reinforce its case to better protect the coolant system in a side-impact crash, Reuter sources say. The fix is expected to cost approximately $1,000 per vehicle including labor, and can be performed in a dealership.

The findings and solutions could help other manufacturers before they introduce new electric vehicles to the market. Tesla and Mini also use liquid-cooled batteries in their electric vehicles, as will Ford in its upcoming electric and plug-in hybrid vehicles. Nissan and Mitsubishi use air-cooled batteries.

Last week fire investigators cleared the Volt and its Siemens-manufactured electric charger of starting a North Carolina house fire that caused $800,000 in damage to a $1.5 million house. Although the cause of the fire has not been determined, investigators say the charger was a victim of the fire, and not the cause of it.